Press welding machine



Sept. 13, 1949. E. J. OPITZ 2,482,023

PRESS WELDING MACHINE Filed Aug. 1948 I 3 Sheets-Sheet 1 /4 If v v 2 115/ I], =3 2 7 Ill.

l I i 1 Q! 37 j 45 S 48 I: 34 L I i-i----- i 59 INVENTOR.

Eric J. 0 0/15 AT TQENEVS.

Sept. 13; 1949. E. J. OPITZ 2,482,023 PRESS WELDING MACHINE Filed Aug. 20, 1948 3 Shets-Sheet 2 NVENT i ric- J. 'o /g v TOENEVS.

INVENZOR.

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Sept. 13, 1949, E. J. OPITZ PRESS WELDING MACHINE Filed Aug. 20, 1948 3 Sheets-Sheet 3 Eric 'J.

Patented Sept. 13, 1949 PRESS WELDING MACHINE Eric J. Opitz, Pleasant Ridge, Mich, assignor to General Motors Corpora corporation of Delaware tion, Detroit, Mich., a

Application August 20, 1948, Serial No. 45,417

8 Claims. 1

This invention relates to pressure welding machines, particularly pressure welding of the type shown, described, and claimed in the Beiderman Patent 2,295,925. These pressure welders operate on the principle of bringing the work and alarge number of welding electrodes in simultaneous contact. Groups of electrodes are served, each by a separate transformer, and the transformers are either individually or in groups successively energized. Only one direct spot weld or two spot welds in series are ordinarily made from a single secondary, but each transformer has two or more secondaries.

In a large welding machine for welding the overlapped flanges of door panels or the large floor pans of automobiles, a large number of electrodes is supported in the machine. In fact in some of the floor pan welders as many as 100 electrodes are supported in the machine. These electrodes are each connected with the piston of a hydraulic cylinder so as to provide a fluid pressure backing for the electrodes when they contact the work and thereby insure an equalization of the pressure of the electrodes on the work notwithstanding irregularities in the work such as elevations or depressions. It is highly desirable to have uniform pressure on the electrodes so as not to vary theresistance of the current passing through the work and thereby impair some of the welds. These are all features and attributes of the pressure welding machine described and claimed in the aforementioned Beiderman patent.

These hydraulic cylinders had been, in the practice of the Beiderman invention, secured to a platen or other support by bolting. One way of securing them has been to bore holes in the platen, provide a large threaded stud on the upper end of the hydraulic cylinder, pass the threaded stud through the bored opening in the platen and clamp the cylinder to the platen by the application of a. large nut to the threaded end of the stud. However each cylinder has required two separate hose connections for delivering the hydraulic pressure to the opposite ends of the cylinder. When the machine has as many as 100 or more electrodes, these many pieces of hose carrying oil under heavy pressure involves a considerable complication in the design of the machine, the location of the elements, and the placing of Welds, in view of the interference posed by such a large number of flexible hoses underneath the platen. This is particularly true when it is realized that each electrode holder must have two hose connections for providing cooling water for the electrodes and each electrode must have a heavy secondary cable connection. In other words, in the pressure system of welding, such as shown and described in the Beiderman patent, each electrode and hydraulic cylinder supporting the electrode has required four flexible hose connections and one heavy secondary cable connection.

Furthermore, these nuts which support the hy draulic cylinders are only accessible from the top of the platens, and in view of the complication introduced into the machine of the large number of small transformers used, and the large number of hose and cable connections, it has been often difiicult to reach the nuts on the top of the platens and turn the nuts with a wrench to release them and the hydraulic cylinder when this becomes necessary for maintenance reasons or for replacement or relocation.

Furthermore, these many hose connections for the oil resulted in a very considerable maintenance service involving expense and delay.

It is an object of the present invention to provide a new arrangement for supporting the electrode cylinders of a pressure welder whereby these cylinders are supported in groups on separate plates or blocks on the platen. These blocks or plates are provided with cored or bored passageways through which the fluid pressure passes to the cylinders and returns from the cylinders, and each of the cylinders is screwed into a threaded socket in the plate or block and has a suitable arrangement of passageways in the cylinder walls and the block to connect the cylinder with the two fluid passageways in the block when the cylinder is screwed home.

Referring to the drawings:

Figure l is a front elevation of part of a pressure welder involving the invention.

Figure 2 is a section on the line 2-2 of Figure 1, showing the plate or block with the cylinders removed from the sockets.

Figure 3 is a section on the line 3-3 of Figure 1.

Figure 4 is a detail of the packing ring.

Figure 5 is a, section on the line 55 of Figure 3.

Figure 6 is a section on the line 66 of Figure 3.

Figure 7 is a detail view of the electrode holder showing the electrode socket in section. 2

Figure 8 is a view of the electrode holder from a angle with respect to the view of Figure 7.

Figure 9 is a diagrammatic View showing the circuits of one transformer.

The platen is designated I. 2 is the table or bed of the machine which is raised and lowered by fluid pressure in cylinder 3. Of course the arrangement might be reversed so that the table is stationary and the platen is raised and lowered with the electrodes. Secured to the platen l are a plurality of blocks or plates 4. These are removably secured in place by screws 5. Each block is provided with a plurality of threaded sockets 6, arranged to receive the threaded upper end of cylinder 1. Each of the blocks has a pair of fluid passageways 8 and 9. These passageways maybe bored or cored in the block. Passageway 8 connects with the threaded socket near its threaded wall by means of passageway lfl. "The'passageway 9 connects with the 'countersunk recess 11 in the threaded socket by intersecting such counter-sunk recess as shown inttheidrawing. These passageways are connected by cross passages, one the passageway l2 andthe other the passageway l3, with pressure main [4 and [5 respectively. These mains are located at the sides of the blocks "andconnected -'-with these cross passageways I2 and l3'byTs 15a.

The piston is guided in part 16 which has an annular recess 'l'i turned' in its mid-portion'and 'a recess T9 at the upper end separated by a spacing ring [9'1]. The sleeve IB'fits over part "l6 andis welded'to it at the lower end. The annular iehamberd'l is connected with chamber I9 bythe "milled-slots l'9l. ZPassage'Hlwill always register with one of the slots 23 in the packing ring 24, and the chamber l 9,-therebybeing in direct communication with'the'passage I leading to and from the passageway 8 in theblock. This assures a proper connection at all times of the chamber 2''! below the piston with-passageway'fl when the oylinder' is screWe'd'home-by applying a wrench to the hexagonal end 23 "of "the cylinder. With this-arrangement these threaded sockets for the =c-ylinders may be arranged closely together as shown in Figure-2 and the cylinder maybe easily =removedor replaced by'merely applying a wrench to thelowe'rhexagonal-end 29of the cylinder and .screwingithe cylinder in or out.

*It is desirable to use separate blocks f or holding groups of electrodes'so that when a change is made "inthe work necessitating the shifting of the lwel-d spots, it is 1 not necessary to revise the wvhole splaten. The'changemay be a relatively :small one, 'so=-all'that is necessary-to do is to re- :moveionei'blcck'and replace it with a new'block. -f0r :the Io1d=bl0ek may be removed and the :01d :iroles'that P formed the sockets plugged with: metal zand new. holes drilled.

This arrangement makes 'it-very easy to make changes in the position-ofzthe welds without too much trouble and maintenance expense. Furthermore, it completely eliminates the flexible zhOSeS "or metal tubes, two ?for each cylinder.

When it is known that the hydraulic pressure maintained in these pressurewelders-has arange from :200 to 400 pounds per square inch, it will be obviousthat-itis a verygreat improvement to eliminate the connectors with .their complications and maintenance problems and substitute the thoroughly reliable .pipe connection to each-cylinder. This insures much'less trouble and expense in maintenance and eliminates danger due -tothe'blowing of the connector-under the heavy pressure maintained.

The -other parts of 'the machinecan -now be described. 2Brepresents"the piston which recipirocates'in the'cylinder and has 'an O ring .packing 21. 28 is the pistonrroduwhich.is alsospacked in part 725 :by :means-of :th'eO ring acking 30.

The end of the piston rod is reduced in diameter and provided with a flat 3| which is secured to bushing 32 by a set screw 33; This bushing has a reduced lower portion which is press fitted or 5 screwed into an insulating sleeve 34 which in turn is press fitted into the electrode-holding block 35. This block or electrode holder is provvided with a tapered recess' 35 into which is driven the electrode 31. The block'has water passages 38 and 39 connected with hoses 40 and H. Insulation 50 is attached to one side of the block. .-Sccuredto the top of the block by bolt 42 and nut 43 is the terminal 44 of the heavy secondary cable 45. It will be noticed that the electrodes maybe angularlyset in the block (see Figures 7 and 8).

The secondaries are in the transformer, independent of one another as shown in Figure 9. "There are two secondaries here shown in connection with one primary 46. Each secondary makes 'a pair J'of series=welds 4'1 bymeason-of -thelec- -trod'e rpads "48 "on the .under side of the work NV. Thisis explained in detail initheptior Beidei trian patent. Of "c'ourse the series weldneed -not be used and only one -weld may be :mad'e by e'ach secondary, :but this "would require a secondary ccable on the under side of l the work and two secondary fcabl'es ifor each weld, 'which introduces -'complications rand undesira'ble difilculties.

.The'claims areas fdllows: "1.111 'a welding machine a support provided "with two independentfluid passageways and provided with threaded recesses made in--=said support having 1 communication with the passageways and 35 :motor icylinders, having each 5a "threaded op'en *end screwed into th'e recess the said open end :making communication with one passageway and each cylinder: having la recess 'in 'the' cylinder wall makingxcommunicatmn withzthe other fluidpas- 4oisageway andithezother end of the cylinder.

,2. in ta xwelding rmachme a support provided 'withttwozindependent fluidapassageways and-provided with .threadedzrecesses made in said sup- 2portrhaving-icommunication With the. passageways 45ia11d3m'0t0r tcylinders, having each a threaded open end screwed into "the recess the said *open end-making:communication with one passageway 'andteach cylindershaving-a recess in thecylinder wall Y making :communication with the other 'fiuid zp way and the rother end of ithe eminder,

and a ring "of :packing ?material pinched between .theend "of each rnylin'der and the-bottom o'f eah recess.

23. In :a welding imachine a support "provided with two independent rfluid passageways and provided with threaded'recesses -made in said sup- :porthaving communication with the passageways :and lmotor cylinders, having each a threaded openiend screwed into the recessthe said open end making-icommuni'caticn withone passageway and :eacncylinderl'havmg a recess in the cylinder wall fmaking communication with -theother fluid passageway and ithe '-'other end -of "the cylinder, and '-a slotted ring of 'packing 'mater'iahpinched between the end'of each-cylinder and'the bottom of each recess.

4."In'a welding mac'hine,the 'combin'ati'onof a supportprov'ided with a pair of fluid passageways through the support :anda plurality of interiorly threaded recesses each .having communication with each passageway, anda motor-:cylinder having a threaded end screwing into said recess and ma-king communication between one end of the 'Tdcylinder and one rpassageway 'and the other end oi the cylinder and the other passageway in the support.

5. In a welding machine, the combination of a support provided with a pair of fluid passageways through the support and a plurality of interiorly threaded recesses each having communication with each passageway, and a motor cylinder having a threaded end screwing into said recess and making communication between one end of the cylinder and one passageway and the other end of the cylinder and the other passageway in the support, the said cylinder having one or more longitudinal slots connecting annular recesses in said cylinder, one of said annular recesses arranged to overlap a passage leading into one of said passageways and the other annular recess having a port into the lower end of the motor cylinder.

6. In a welding machine, the combination of a support provided with a pair of fluid passageways through the support and a plurality of interiorly threaded recesses each having communication with each passageway, and a motor cylinder having a threaded end screwing into said recess and making communication between one end of the cylinder and one passageway and the other end of the cylinder and the other passageway in the support, the said cylinder having one or more longitudinal slots connecting annular recesses in said cylinder, one of said annular recesses arranged to overlap a passage leading into one of said passageways and the other annular recess having a port into the lower end of the motor cylinder, and a slotted packing ring interposed between the threaded end of each cylinder and the bottom of each threaded recess to seal the cylinder in the support with one of the slots overlapping the outlet passageway on the support and the inner annular recess of the motor cylinder.

7. In a press welder a platen, a plurality of plates or blocks removably secured to one face of the platen, each plate or block provided with fluid passageways and a plurality of threaded circular recesses in communication with the fluid passageways and motor cylinders provided with recessed walls screwing into said recesses by reason of threads on one of their ends and by said recessed walls thereby making communication between one end of the cylinder and one passageway and the other end of the cylinder and the other passageway, and fluid mains connected with the passageways in said blocks.

8. In a press welder a platen, a plurality of plates or blocks removably secured to one face of the platen, each plate or block provided with fluid passageways and a plurality of threaded circular recesses in communication with the fluid passageways and motor cylinders provided with recessed walls screwing into said recesses by reason of threads on one of their ends and by said recessed walls thereby making communication between one end of the cylinder and one passageway and the other endfof the cylinder and the other passageway, and fluid mains connected with the passageways in said blocks, said mains comprising pipe lines on each of two sides of the blocks having T connections with the passageways in the blocks.

ERIC J. OPITZ.

REFERENCES CITED The following references are of record in the file of this patent: 

